TIMOTHY A. CLARY/AFP/Getty Images(SEOUL, South Korea) -- The U.N. Security Council on Thursday brushed off a threat by North Korea to launch a "pre-emptive nuclear strike" and voted to impose tough new sanctions on the country as punishment for its nuclear weapon and ballistic missile program.

China, North Korea's staunchest ally, joined the U.S. and other members of the Security Council to make the vote unanimous.

The vote came hours after Pyongyang, which has been delivered a series of belligerent statements in recent weeks, said that it would "exercise its right for pre-emptive nuclear strike to destroy the strongholds of the aggressors."

The tough talk from North Korea also comes as the U.S. and South Korean begin joint military maneuvers.

The U.S. dismissed the North Korean threat.

"North Korean threats of provocations will only further isolate North Korea and undermine international efforts to ensure peace and stability in Northeast Asia," Pentagon spokeswoman Lt. Col. Cathy Wilkinson said.

In recent days, North Korea has vowed to turn Seoul and Washington into a "sea of fire," has imposed no-sail/no-fly zones along its coasts, and warned that it might end the armistice that halted the Korean War in 1953 without a peace treaty.

The latest sanctions target North Korean banks, diplomats and officials at a company identified as the country's primary arms dealer.

"Taken together these sanctions will bite and bite hard," Susan Rice, the U.S. ambassador to the United Nations, said on Thursday.

The resolution also prohibits the sale of luxury goods to North Korean leadership who Rice says have been living large while their people suffer.

"North Korea's ruling elite who have been living large while impoverishing their people will pay a direct price for this nuclear test," she said.

Rice says the resolution will make it harder for North Korea to finance its nuclear weapons program.